funeral director vs undertaker

funeral director and undertaker both are nouns.

Word	Noun	Adjective	Verb	Adverb
funeral director	Yes	No	No	No
undertaker	Yes	No	No	No

As nouns, funeral director and undertaker are synonyms defined as:

funeral director and undertaker: one whose business is the management of funerals

Other synonyms of funeral director include funeral undertaker, mortician.

funeral director (noun)	undertaker (noun)
one whose business is the management of funerals	one whose business is the management of funerals